My 6yo son plays Skylander Swap Force on Wii console.
He has 2 giants figures (on cards written "skylander giants" and they have orange base) : Whirlwind and Trigger Happy.
None of them can open the giants chest ("only giants can open this chest").
Why is that and which figures does he need?
So, with the early Skylanders games (excluding Spyro's Adventure), two main "types" of character figures released with the game, standard characters which are the smaller ones (and these are split further into new, reposes and lightcore), then special ones which come with extra effects - the Giants are one of these, and they're figures that are bigger than the standard releases in their line (thus, Giants). Whirlwind and Trigger Happy are two of the smaller figures from the game (and as they originate from the first game, the orange base versions are known as "reposes").
There are eight Giant characters - Bouncer, Crusher, Eye-Brawl, Hot Head, Ninjini, Swarm, Thumpback and Tree Rex.